Molda 21

Molda 21 is a formulated hemihydrate plaster which is used in ceramics to produce working moulds for the slip casting of sanitaryware, tableware or refractory when mould life is important in particular with abrasive clays such as Coarse Fire Clay and when a limited plaster expansion is needed.

This product can be also used for modelling plasterwork

Benefits

Adapated for ceramics slip casting with abrasive clay

Balance between mechanical properties and absorption capability

controlled in expansion for easy plaster demoulding

Markets

Ceramics

Applications

Sanitaryware

Technical data

Chemical Properties
Chemical Composition	CaSO₄.1/2H₂O
Chemical Name	Calcium sulphate hemihydrate
Colour	white
Minimum gypsum purity %	91

Setting Parameters
Initial setting time (minutes)	25
Vicat Ring Fluidity (cm)	20

Physical Properties
Particle Size (% weight retained)	0.05% at 200 µm 2% at 100 µm

Plaster to Water Ratio
Plaster to water mix ratio (by weight)	100/63
Plaster to Water Ratio (by weight)	1.60:1
Water to plaster ratio (by weight)	63%

Instructions for use

The recommended plaster to water ratio is between 1.50:1 and 1.60:1, with a mixing time of approx. 2 to 4 minutes, depending on batch size and plaster shop process.Mixing utensils should always be clean and free from set plaster. Use distilled water only. For consistent results, attention must be given to the correct proportioning and mixing of the plaster and water.Add the weighed quantity of plaster slowly into the measured volume of water and allow to soak. Do not mix fresh plaster with that which has been mixed for some time previouslyChanges to plaster to water ratio will influence product performance, particularly setting time and strength and absorption capability.The following graphs help illustrate how varying ratios will affect compressive strength and water absorption.

Packaging and shelf life

Bag

Packaging available : 25 kg

Shelf life : 10

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